+++ /dev/null
-#ifndef _LINUX_RING_BUFFER_BACKEND_H
-#define _LINUX_RING_BUFFER_BACKEND_H
-
-/*
- * linux/ringbuffer/backend.h
- *
- * Copyright (C) 2008-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Ring buffer backend (API).
- *
- * Dual LGPL v2.1/GPL v2 license.
- *
- * Credits to Steven Rostedt for proposing to use an extra-subbuffer owned by
- * the reader in flight recorder mode.
- */
-
-/* Internal helpers */
-#include "backend_internal.h"
-#include "frontend_internal.h"
-
-/* Ring buffer backend API */
-
-/* Ring buffer backend access (read/write) */
-
-extern size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb,
- size_t offset, void *dest, size_t len);
-
-extern int __lib_ring_buffer_copy_to_user(struct lib_ring_buffer_backend *bufb,
- size_t offset, void __user *dest,
- size_t len);
-
-extern int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb,
- size_t offset, void *dest, size_t len);
-
-extern struct page **
-lib_ring_buffer_read_get_page(struct lib_ring_buffer_backend *bufb, size_t offset,
- void ***virt);
-
-/*
- * Return the address where a given offset is located.
- * Should be used to get the current subbuffer header pointer. Given we know
- * it's never on a page boundary, it's safe to write directly to this address,
- * as long as the write is never bigger than a page size.
- */
-extern void *
-lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb,
- size_t offset);
-extern void *
-lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb,
- size_t offset);
-
-/**
- * lib_ring_buffer_write - write data to a buffer backend
- * @config : ring buffer instance configuration
- * @ctx: ring buffer context. (input arguments only)
- * @src : source pointer to copy from
- * @len : length of data to copy
- *
- * This function copies "len" bytes of data from a source pointer to a buffer
- * backend, at the current context offset. This is more or less a buffer
- * backend-specific memcpy() operation. Calls the slow path (_ring_buffer_write)
- * if copy is crossing a page boundary.
- */
-static inline
-void lib_ring_buffer_write(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer_ctx *ctx,
- const void *src, size_t len)
-{
- struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
- struct channel_backend *chanb = &ctx->chan->backend;
- size_t sbidx, index;
- size_t offset = ctx->buf_offset;
- ssize_t pagecpy;
- struct lib_ring_buffer_backend_pages *rpages;
- unsigned long sb_bindex, id;
-
- offset &= chanb->buf_size - 1;
- sbidx = offset >> chanb->subbuf_size_order;
- index = (offset & (chanb->subbuf_size - 1)) >> PAGE_SHIFT;
- pagecpy = min_t(size_t, len, (-offset) & ~PAGE_MASK);
- id = bufb->buf_wsb[sbidx].id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = bufb->array[sb_bindex];
- CHAN_WARN_ON(ctx->chan,
- config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- if (likely(pagecpy == len))
- lib_ring_buffer_do_copy(config,
- rpages->p[index].virt
- + (offset & ~PAGE_MASK),
- src, len);
- else
- _lib_ring_buffer_write(bufb, offset, src, len, 0);
- ctx->buf_offset += len;
-}
-
-/*
- * This accessor counts the number of unread records in a buffer.
- * It only provides a consistent value if no reads not writes are performed
- * concurrently.
- */
-static inline
-unsigned long lib_ring_buffer_get_records_unread(
- const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf)
-{
- struct lib_ring_buffer_backend *bufb = &buf->backend;
- struct lib_ring_buffer_backend_pages *pages;
- unsigned long records_unread = 0, sb_bindex, id;
- unsigned int i;
-
- for (i = 0; i < bufb->chan->backend.num_subbuf; i++) {
- id = bufb->buf_wsb[i].id;
- sb_bindex = subbuffer_id_get_index(config, id);
- pages = bufb->array[sb_bindex];
- records_unread += v_read(config, &pages->records_unread);
- }
- if (config->mode == RING_BUFFER_OVERWRITE) {
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- pages = bufb->array[sb_bindex];
- records_unread += v_read(config, &pages->records_unread);
- }
- return records_unread;
-}
-
-ssize_t lib_ring_buffer_file_splice_read(struct file *in, loff_t *ppos,
- struct pipe_inode_info *pipe,
- size_t len, unsigned int flags);
-loff_t lib_ring_buffer_no_llseek(struct file *file, loff_t offset, int origin);
-
-#endif /* _LINUX_RING_BUFFER_BACKEND_H */